osfmk/prng/random.h

   1 /*
   2  * Copyright (c) 2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #ifndef _PRNG_RANDOM_H_
  30 #define _PRNG_RANDOM_H_
  31
  32 __BEGIN_DECLS
  33
  34 #ifdef XNU_KERNEL_PRIVATE
  35
  36 #define ENTROPY_BUFFER_BYTE_SIZE 64
  37
  38 #define ENTROPY_BUFFER_SIZE (ENTROPY_BUFFER_BYTE_SIZE / sizeof(uint32_t))
  39
  40 typedef struct entropy_data {
  41         /*
  42          * TODO: Should index_ptr be volatile?  Are we exposed to any races that
  43          * we care about if it is not?
  44          */
  45         uint32_t *index_ptr;
  46         uint32_t buffer[ENTROPY_BUFFER_SIZE];
  47 } entropy_data_t;
  48
  49 extern entropy_data_t EntropyData;
  50
  51 /* Trace codes for DBG_SEC_KERNEL: */
  52 #define ENTROPY_READ(n) SECURITYDBG_CODE(DBG_SEC_KERNEL, n) /* n: 0 .. 3 */
  53
  54 /*
  55  * Early_random implementation params: */
  56 #define EARLY_RANDOM_SEED_SIZE (16)
  57 #define EARLY_RANDOM_STATE_STATIC_SIZE (264)
  58
  59 #if defined (__x86_64__)
  60 #define current_prng_context()  (current_cpu_datap()->cpu_prng)
  61 #define master_prng_context()   (cpu_datap(master_cpu)->cpu_prng)
  62 #elif defined (__arm__) || defined(__arm64__)
  63 #include <arm/cpu_data_internal.h>              // For MAX_CPUS
  64 #define current_prng_context()  (getCpuDatap()->cpu_prng)
  65 #define master_prng_context()   (cpu_datap(master_cpu)->cpu_prng)
  66 #else
  67 #error architecture unknown
  68 #endif
  69
  70 #include <corecrypto/ccdrbg.h>
  71 #include <corecrypto/ccsha1.h>
  72
  73 typedef void (*ccdrbg_factory_t)(struct ccdrbg_info *info, const void *custom);
  74
  75 extern void     ccdrbg_factory_yarrow(struct ccdrbg_info *info, const void *custom);
  76
  77 void prng_factory_register(ccdrbg_factory_t factory);
  78 void prng_cpu_init(int cpu);
  79
  80 void entropy_buffer_read(void *buffer, size_t *count);
  81 void entropy_boot_trace(void);
  82
  83 /*
  84  * Wrapper for requesting a CCDRBG operation.
  85  * This macro makes the DRBG call with pre-emption disabled to ensure that
  86  * any attempt to block will cause a panic. And the operation is timed and
  87  * cannot exceed 10msec (for development kernels).
  88  * But skip this while we retain Yarrow.
  89  */
  90 #define YARROW 1
  91 #if YARROW
  92 #define PRNG_CCDRBG(op)                                 \
  93 MACRO_BEGIN                                             \
  94         op;                                             \
  95 MACRO_END
  96 #else
  97 #define PRNG_CCDRBG(op)                                 \
  98 MACRO_BEGIN                                             \
  99         uint64_t        start;                          \
 100         uint64_t        stop;                           \
 101         disable_preemption();                           \
 102         start = mach_absolute_time();                   \
 103         op;                                             \
 104         stop = mach_absolute_time();                    \
 105         enable_preemption();                            \
 106         assert(stop - start < 10*NSEC_PER_MSEC ||       \
 107                machine_timeout_suspended());            \
 108         (void) start;                                   \
 109         (void) stop;                                    \
 110 MACRO_END
 111 #endif
 112
 113 #endif /* XNU_KERNEL_PRIVATE */
 114
 115 /* /dev/random's PRNG is reseeded after generating this many bytes: */
 116 #define RESEED_BYTES (17597)
 117
 118 __END_DECLS
 119
 120 #endif /* _PRNG_RANDOM_H_ */